In the above co-pending application of S. E. Pedersen, Ser. No. 889,785, which application is incorporated herein by reference, there is disclosed and claimed a method for the preparation of maleic anhydride by oxidizing an unsaturated aliphatic hydrocarbon in the vapor phase at temperatures of from about 300.degree. C. to 600.degree. C. and pressures of from about ambient to 1000 psig with oxygen or an oxygen-containing gas, such as air, in the presence of a single phase vanadium(IV)bis(metaphosphate) catalyst. This catalyst which may be prepared by the methods disclosed in the above noted co-pending Pedersen application or in an article by Bruce C. Tofield et al, J.A.C.S., Dalton Transactions, Part II, 1975, pp. 1806-1810 and G. Ladwig, Z. Chem., 1968, Vol. 8, p. 307, which after activation or conditioning, is a good oxidation catalyst for unsaturated aliphatic hydrocarbons to produce maleic anhydride, suffers from a disadvantage in that it has an intrinsic surface area of only 0.30 to 0.50 m.sup.2 /gm. Such limited intrinsic surface area is generally undesirable because the activity of the oxides of vanadium and phosphorus are directly related to the intrinsic surface area, particularly when employed as oxidation catalysts to prepare maleic anhydride.